A palm oil-based lubricant for drilling fluids and a method of making the same

Abstract

The present application relates to the technical fields of drilling fluid treating agent, in particular to a palm oil-based lubricant for drilling fluid and a preparation method thereof, the palm oil-based lubricant comprises 65-90% of epoxy palm oil, 0.1-10% of emulsifier, 0.1-10% of antioxidant, 0.1-10% of pour point depressant and 0.1-10% of anti-wear and drag-reducing agent by weight percentage; wherein the antioxidant is obtained by mixing sulfide and phenolic ester in a weight ratio of 1:1. The present application improves the oxidation stability of palm oil by epoxy modification and the two technical means of preferred complexing agent, reduces the tackiness, reduces the hydrolysis reaction of palm oil molecules, makes it have good temperature resistance and lubricating performance, not only meets the needs of conventional wells, but also can be used in double-branch horizontal wells, deep wells or ultra-deep wells, complex exploration wells and other drilling operations which have high requirements for the high temperature resistance and lubricating performance of lubricant.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drilling fluid treatment agents, in particular to a palm oil-based lubricant for drilling fluids and a preparation method thereof. BACKGROUND

[0002] In order to reduce friction, the amount of lubricant in water-based drilling fluid is increasing in the eastern oil field of Ecuador, which is gradually developed by large displacement horizontal wells. Currently, there is an intention to use oil-based drilling fluid. However, the disposal of oil-containing drill cuttings generated by using conventional white oil and diesel-based drilling fluid is difficult and expensive. Ecuador is the largest palm plantation area in South America, and palm oil is cheap and widely available. Palm oil is generally non-toxic, low in cost, stable in nature, and has a high smoke point, with a smoke point and aniline point higher than 65℃. These characteristics make palm oil a good base oil for full oil lubricants.

[0003] In addition, palm oil not only has the advantages of strong biodegradability, low cost, and environmental friendliness, but also has the basic functions of oil-based drilling fluid base fluid. Compared with mineral oil-based and conventional synthetic-based drilling fluids, the disposal cost of palm oil drilling fluid waste is low. Palm oil has a high content of saturated fatty acids and good stability. However, palm oil is a full natural plant oil, which is a mixture of mixed fatty acid glycerol triesters and a small amount of oleic acid, etc. The carbon chain length is mainly C12~C18. The fatty acids include saturated fatty acids and unsaturated fatty acids containing C=C double bonds, of which the unsaturated fatty acids account for about 50%. Under high temperature oxidation conditions, palm oil is prone to hydrolysis, saponification, and foaming. The composition structure of palm oil is quite different from that of white oil and diesel oil. The capacity of the drilling fluid system for external fluids and pollutants is relatively small. In particular, after high temperature action, the rheological properties such as thickening are difficult to control.

[0004] In the prior art, a Chinese patent application with the publication number CN102199480A and the publication date of September 28, 2011 is disclosed. The technical solution disclosed in the patent document is as follows: a method for preparing a palm oil lubricant, which comprises the following steps: preparing epoxy palm oil from palm oil; reacting the epoxy palm oil with acetic acid to obtain palm oil acetic acid isomerate after purification of the product; heating the palm oil acetic acid isomerate to 35~50℃, adding an additive, and stirring at 50~60℃ for 0.5~1 hours.

[0005] The above technical solution has the following problems in actual use: the above palm oil-based lubricant can only be used at low temperatures and cannot withstand high temperatures, and cannot be used for drilling fluids.

[0006] However, there are few analyses and research applications of "high-temperature-resistant palm oil-based lubricants". For palm oil-based lubricants, the key technical problems to be solved are: reducing hydrolysis under high temperature conditions and reducing condensation under low temperature conditions. SUMMARY

[0007] To solve the above technical problems, the application provides a palm oil-based lubricant for drilling fluid and a preparation method thereof, which improves the oxidation stability of palm oil, reduces the tackiness, reduces the hydrolysis reaction of palm oil molecules, has good temperature resistance and lubricating performance, and can be used in double-branch horizontal wells, deep wells or ultra-deep wells, complex exploration wells and other drilling operations with high requirements for high temperature resistance and lubricating performance of the lubricant.

[0008] The application is achieved by adopting the following technical scheme:

[0009] The palm oil-based lubricant for drilling fluid comprises 65-90% of epoxy palm oil, 0.1-10% of an emulsifier, 0.1-10% of an antioxidant, 0.1-10% of a pour point depressant and 0.1-10% of an anti-wear and drag reduction agent by weight percentage.

[0010] The antioxidant is obtained by mixing sulfide BASF-PS802 and phenolic ester T135 at a weight ratio of 1:1.

[0011] The preparation method of the epoxy palm oil comprises the following steps:

[0012] a. Preparation of an epoxidation agent: 7 parts of acetic acid or formic acid, 18 parts of hydrogen peroxide and 0.1 part of concentrated H2SO4 are weighed according to weight parts, and then mixed uniformly at 40 DEG C to prepare an epoxidation agent; the concentration of the hydrogen peroxide is 30%;

[0013] b. Epoxidation reaction: 35 parts of palm oil are weighed according to weight parts, heated to 40 DEG C, and then the epoxidation agent prepared in a is added at a constant speed, and the addition is completed within 1 h, and then the reaction is carried out at a temperature of 65 DEG C for 6 h;

[0014] c. After the reaction is completed, the layers are separated, the lower layer of waste liquid is removed, the upper layer of oil is washed with hot dilute alkali solution first, and then washed with distilled water until neutral, and then dehydrated and dried.

[0015] The emulsifier comprises an ionic surfactant or a non-ionic surfactant.

[0016] The emulsifier comprises alkyl sulfate, alkyl benzene sulfonate, phosphate, sulfate, polyol fatty acid ester, oleate, polyvinyl alcohol, polyacrylamide, polyglycerol ester and derivatives thereof.

[0017] The pour point depressant includes polymethacrylate, acetic acid and vinyl acetate, maleic anhydride copolymer, hydroxy stearin, fatty acid glyceride or mixture thereof.

[0018] The anti-wear friction reducer includes one or more of sulfurized olefins, metal thiophosphate, metal dialkyldithiophosphate, phosphate or salt thereof, phosphite or salt thereof, thio carbamate-containing compound, molybdenum dithiocarbamate.

[0019] A preparation method of a palm oil-based lubricant for drilling fluid, comprising the following steps:

[0020] Step S1. Add epoxy palm oil in a closed reaction kettle, then add emulsifier, heat and stir until the temperature reaches 50 DEG C, and then stir until the emulsifier is completely dissolved;

[0021] Step S2. Add antioxidant and stir until uniform;

[0022] Step S3. Add pour point depressant and stir until uniform;

[0023] Step S4. Finally, add anti-wear friction reducer and stir until completely dissolved, thereby obtaining the palm oil-based lubricant.

[0024] Compared with the prior art, the beneficial effects of the present application are as follows:

[0025] 1. The palm oil-based lubricant for water-based drilling fluid is prepared by using palm oil as a basic raw material, preparing epoxy palm oil, and adding special functional additives, and has good dispersibility, strong stability, can resist 120 DEG C high temperature, has no fluorescence, has no any influence on geological logging, effectively solves the lubrication and torque and friction reduction problems in the process of horizontal well drilling, and also solves the key technical problems of the existing palm oil-based lubricant: hydrolysis reduction technology under high temperature conditions and pour point depression technology under low temperature conditions.

[0026] Specifically, according to the epoxy palm oil preparation method of the present application, the palm oil can be maximally epoxidized by specific palm oil and epoxidation agent ratio and the reaction conditions, and the performance of the prepared epoxy palm oil is optimized, so that it is more suitable for the preparation of subsequent palm oil-based lubricant, and provides the best lubrication effect in high temperature drilling fluid.

[0027] Specifically, the temperature resistance of the lubricant of the present application is due to the synergistic effect of the two antioxidants used, and the cooperation with the selected anti-wear and drag-reducing agent, further improving the temperature resistance of the system. Under the selected ratio of the present application, it is ensured that the lubricant can resist 120°C high temperature. In addition, the emulsifier used in the present application also has the ability to improve the lubrication coefficient. Under the ratio of the present application, together with the antioxidant and the anti-wear and drag-reducing agent, it is ensured that the lubricant can still provide good lubrication characteristics at 120°C.

[0028] 2、The present application has obvious lubricating, torque-reducing and friction-reducing effect. After adding 0.5% palm oil-based lubricant in the base slurry, the extreme pressure lubrication coefficient is greatly reduced, and the lubrication coefficient reduction rate reaches an average of 90.2%.

[0029] 3、The present application has good compatibility with on-site drilling fluid. After adding, the on-site drilling fluid does not separate, and there is no caking phenomenon. In addition to the improved lubrication performance of the on-site drilling fluid, the rheological performance is stable and there is no abnormal change phenomenon.

[0030] 4、The present application is non-fluorescent and does not affect geological logging. Since it is non-fluorescent, it has no effect on geological logging, and the authenticity of the cuttings is maintained.

[0031] 5、The present application is environmentally friendly, non-toxic and easy to biodegrade, and is a biodegradable lubricant.

[0032] 6、In the present application, when preparing the palm oil-based lubricant for drilling fluid, the prepared epoxy palm oil does not need to be further treated, only the various additives need to be added to the epoxy palm oil in turn. The preparation method is simple, and the reaction conditions in the preparation process are also low.

[0033] 7、In the present application, when preparing the palm oil-based lubricant, the components are added in turn, compared with the conventional technical scheme of adding all components, the palm oil-based lubricant manufactured according to the order of the present application can ensure the dissolution of each component, fully play the effect of each component, and ensure that the added additives do not directly react with each other, so that the whole system maintains the best effect. DETAILED DESCRIPTION

[0034] Example 1

[0035] A palm oil-based lubricant for drilling fluid, by weight percentage, includes 65% of epoxy palm oil, 10% of emulsifier, 10% of antioxidant, 5% of pour point depressant and 10% of anti-wear and drag-reducing agent. The antioxidant is a mixture of thioether and phenolic ester in a weight ratio of 1:1.

[0036] The emulsifier includes an ionic surfactant or a non-ionic surfactant, and can be one or more emulsifiers in a composite in any proportion. The emulsifier includes an alkyl sulfate, an alkyl benzene sulfonate, a phosphate, a sulfuric ester, a polyhydric alcohol fatty acid ester, an oleate, a polyvinyl alcohol, a polyacrylamide, a polyglycerol ester, and the like, and derivatives thereof. The pour point depressant includes a polymethacrylate, an acetic acid and vinyl acetate, a maleic anhydride copolymer, a hydroxy stearin, a fatty acid glycerol ester, or a mixture thereof. The anti-wear friction reducer includes one or more of a sulfurized olefin, a metal thiophosphate, a metal dialkyldithiophosphate, a phosphate ester or salt thereof, a phosphite ester or salt thereof, a thiocarbamic acid-containing compound, and a molybdenum dithiocarbamate. The sulfide is BASF-PS802, and the phenolic ester is T135.

[0037] The epoxy palm oil is prepared by the following method: 7 parts of acetic acid or formic acid, 18 parts of hydrogen peroxide, and 0.1 part of concentrated H2SO4 are weighed, and mixed uniformly at 40°C to prepare an epoxy reagent. The concentration of the hydrogen peroxide is 30%. 35 parts of palm oil is weighed, heated to 40°C, and then the prepared epoxy reagent is added dropwise at a constant speed, and the dropwise addition is completed within 1 hour. Then, the reaction is carried out at a temperature of 65°C for 6 hours. After the reaction is completed, the reaction mixture is allowed to stand and separate into two layers. The lower layer of waste liquid is removed, and the upper layer of oil is washed with a hot dilute alkali solution, and then washed with distilled water until neutral. The oil is dehydrated and dried to obtain the epoxy palm oil.

[0038] The palm oil-based lubricant is prepared by the following method: the epoxy palm oil and the emulsifier are sequentially added to a sealed reaction kettle, heated to 50°C, and stirred for 25 minutes. Then, the sulfide and the phenolic ester are added, stirred for 15 minutes, the pour point depressant is added, stirred for 15 minutes, and finally the anti-wear friction reducer is added, stirred for 25 minutes until completely dissolved, to obtain the palm oil-based lubricant.

[0039] Example 2

[0040] A palm oil-based lubricant for drilling fluid includes, by weight percentage, 90% of epoxy palm oil, 0.1% of an emulsifier, 0.1% of an antioxidant, 0.1% of a pour point depressant, and 9.7% of an anti-wear friction reducer. The antioxidant is a mixture of a sulfide and a phenolic ester in a weight ratio of 1:1.

[0041] The emulsifier includes an ionic surfactant or a non-ionic surfactant, and can be one or more emulsifiers in any proportion. The emulsifier includes alkyl sulfate, alkyl benzene sulfonate, phosphate, sulfate, polyol fatty acid ester, oleate, polyvinyl alcohol, polyacrylamide, polyglycerol ester, and derivatives thereof. The pour point depressant includes polymethacrylate, acetic acid and vinyl acetate, maleic anhydride copolymer, hydroxystearin, fatty acid glyceride, or a mixture thereof. The anti-wear friction reducer includes one or more of sulfurized olefins, metal thiophosphate, metal dialkyldithiophosphate, phosphate or salt thereof, phosphite or salt thereof, thioaminoformic acid ester-containing compound, and molybdenum dithioaminoformic acid ester. The sulfide is BASF-PS802, and the phenolic ester is T135.

[0042] The preparation method of the epoxy palm oil and the preparation method of the palm oil-based lubricant are the same as those in Embodiment 1, and details are not repeated herein.

[0043] Embodiment 3

[0044] A palm oil-based lubricant for drilling fluid includes, in percentage by weight, 79.9% of epoxy palm oil, 5% of emulsifier, 5% of antioxidant, 10% of pour point depressant, and 0.1% of anti-wear friction reducer. The antioxidant is a mixture of sulfide and phenolic ester in a weight ratio of 1:1.

[0045] The emulsifier includes an ionic surfactant or a non-ionic surfactant, and can be one or more emulsifiers in any proportion. The emulsifier includes alkyl sulfate, alkyl benzene sulfonate, phosphate, sulfate, polyol fatty acid ester, oleate, polyvinyl alcohol, polyacrylamide, polyglycerol ester, and derivatives thereof. The pour point depressant includes polymethacrylate, acetic acid and vinyl acetate, maleic anhydride copolymer, hydroxystearin, fatty acid glyceride, or a mixture thereof. The anti-wear friction reducer includes one or more of sulfurized olefins, metal thiophosphate, metal dialkyldithiophosphate, phosphate or salt thereof, phosphite or salt thereof, thioaminoformic acid ester-containing compound, and molybdenum dithioaminoformic acid ester. The sulfide is BASF-PS802, and the phenolic ester is T135.

[0046] The preparation method of the epoxy palm oil and the preparation method of the palm oil-based lubricant are the same as those in Embodiment 1, and details are not repeated herein.

[0047] Embodiment 4

[0048] A palm oil-based lubricant for drilling fluid, comprising 80 parts of epoxy palm oil, 3 parts of emulsifier, 3 parts of antioxidant, 0.5 parts of pour point depressant and 5 parts of anti-wear and friction-reducing agent by weight. Wherein the emulsifier is glyceryl monooleate, the pour point depressant is hydroxystearin, and the anti-wear and friction-reducing agent is zinc dialkyldithiophosphate T203.

[0049] The preparation method of the epoxy palm oil is as follows: 7 parts of acetic acid and 18 parts of 30% hydrogen peroxide are mixed uniformly, 0.1 part of concentrated sulfuric acid is added, and the mixture is mixed uniformly at 40°C and reserved. 35 parts of palm oil is weighed in a three-necked flask, heated to 40°C, and the above mixture is added at a constant speed. The reaction is carried out at 65°C for 6 hours. Then the sample is allowed to stand and separate into layers. The lower layer of waste liquid is removed first to obtain the upper layer of oil. Then the oil is washed with hot dilute alkali solution, and then washed with distilled water until neutral. After drying, the epoxy palm oil is obtained.

[0050] The preparation method of the palm oil-based lubricant is as follows: in a closed reaction kettle, 80 parts of epoxy palm oil, 3 parts of emulsifier, 3 parts of antioxidant, 0.5 parts of pour point depressant and 5 parts of anti-wear and friction-reducing agent are added in sequence. After heating to 50°C and stirring for 25 minutes, 3 parts of antioxidant is added and stirred for 15 minutes. Then 0.5 parts of pour point depressant is added and stirred for 15 minutes. Finally, 5 parts of anti-wear and friction-reducing agent is added and stirred for 25 minutes until all are dissolved to obtain the palm oil-based lubricant.

[0051] Wherein, the same epoxy palm oil, emulsifier, pour point depressant and anti-wear and friction-reducing agent are used to prepare different palm oil-based lubricants by adjusting the specific type of antioxidant. Specifically, when 3 parts of antioxidant is 3 parts of sulfide BASF-PS802, palm oil-based lubricant A is prepared. When 3 parts of antioxidant is 3 parts of phenolic ester T135, palm oil-based lubricant B is prepared. When 3 parts of antioxidant is 1.5 parts of sulfide BASF-PS802 and 1.5 parts of phenolic ester T135, palm oil-based lubricant C is prepared.

[0052] The performance of the above palm oil-based lubricant A, palm oil-based lubricant B and palm oil-based lubricant C is tested, including:

[0053] (1) According to the technical specification index requirements of Q / SY17088-2016 liquid lubricant for drilling fluid, blank base slurry, sample added with 0.5% palm oil, sample added with 0.5% palm oil-based lubricant A, sample added with 0.5% palm oil-based lubricant B and sample added with 0.5% palm oil-based lubricant C are prepared, and the performance of the three samples is tested according to the standard method, as shown in the following table 1.

[0054] Table 1 Performance determination of palm oil-based lubricant in base slurry

[0055]

[0056] The experimental results show that, compared with the base paste, the addition of 0.5% palm oil, 0.5% palm oil-based lubricant A, 0.5% palm oil-based lubricant B and 0.5% palm oil-based lubricant C can reduce the lubrication coefficient by 66.0%, 77.4%, 71.7% and 90.2% respectively after hot rolling, and the apparent viscosity increases by 5.0 mPa·s, 5.0 mPa·s, 4.0 mPa·s and 2.5 mPa·s respectively. The experimental results show that the addition of palm oil can reduce the lubrication coefficient of the system, but the addition of the prepared palm oil-based lubricant can improve the lubrication efficiency to a greater extent. In addition, during the preparation of the palm oil-based lubricant, the use of sulfide and phenolic ester complex antioxidant can further improve the antioxidant effect of the palm oil-based lubricant. It shows that sulfide and phenolic ester have a synergistic effect, and their simultaneous use can improve the temperature resistance of the system.

[0057] Therefore, the palm oil-based lubricant C prepared according to the present application meets the requirement of the standard Q / SY17088-2016 that the reduction rate of the lubrication coefficient is greater than 80% under the test conditions, and can be applied as a lubricant in drilling fluid; and compared with untreated palm oil, not only the lubrication performance is significantly improved, but also the high temperature resistance is obviously improved.

[0058] (2) Three drilling fluids were prepared according to the formula 400ml water + 1.0% ASR-1 modified starch + 0.3% XCD xanthan gum + 0.5% PAC-L low viscosity polyanionic cellulose + 0.2% PAC-H high viscosity polyanionic cellulose + caustic soda to adjust pH to 8, 0.5% palm oil was added to one of them, 0.5% palm oil-based lubricant C was added to one of them, and the lubrication performance of the drilling fluid system before and after 120℃x16h hot rolling was measured, as shown in Table 2 below.

[0059] Table 2 Performance determination of palm oil-based lubricant in drilling fluid system

[0060]

[0061] The experimental results show that the addition of palm oil-based lubricant C to the drilling fluid can reduce the lubrication coefficient by 88.9% compared with the blank drilling fluid, which still meets the lubrication performance requirement of the drilling fluid, and significantly improves the temperature resistance of palm oil.

[0062] (3) Three drilling fluids were prepared according to the formula 400ml water + 1.0% ASR-1 modified starch + 0.3% XCD xanthan gum + 0.5% PAC-L low viscosity polyanionic cellulose + 0.2% PAC-H high viscosity polyanionic cellulose + caustic soda to adjust pH to 8, 0.5% palm oil-based lubricant C was added to one of them, 0.5% palm oil-based lubricant C was added to one of them, and the performance of the drilling fluid system before and after 120℃x16h hot rolling was measured, as shown in Table 3 below.

[0063] Table 3 Performance comparison of palm oil-based lubricant and existing lubricant

[0064]

[0065] The experimental results show that the lubricating coefficient of the drilling fluid with palm oil-based lubricant C and the drilling fluid with existing drilling fluid lubricant is reduced by 88.9% and 70.4% respectively after hot rolling compared with the blank drilling fluid, which indicates that the performance of palm oil-based lubricant C is better than that of the existing drilling fluid lubricant, and the palm oil-based lubricant C can effectively reduce the lubricating coefficient of the drilling fluid system and is applied in engineering.

[0066] In summary, other various corresponding transformation schemes made by the ordinary skilled in the art without creative mental labor according to the technical scheme and technical concept of the present application after reading the present application file all belong to the scope protected by the present application.

Claims

1. A palm oil based lubricant for drilling fluids characterised in that: 65%—90% of the epoxy palm oil, 0.1%—10% of the emulsifier, 0.1%—10% of the antioxidant, 0.1%—10% of the pour point depressant and 0.1%—10% of the anti-wear and friction-reducing agent; wherein the antioxidant is a mixture of thioether BASF-PS802 and phenolic ester T135 in a weight ratio of 1:1; the epoxy palm oil is prepared by epoxidation of raw materials containing palm oil and an epoxidizing agent; the epoxidizing agent is generated by reaction of acetic acid or formic acid with hydrogen peroxide under catalysis of concentrated H2SO4; the emulsifier is a non-ionic surfactant, including polyol fatty acid ester, oleate, polyglycerol ester and derivatives thereof; the pour point depressant is a fatty acid glyceride; and the anti-wear and friction-reducing agent is a metal salt of thiophosphoric acid.

2. A palm oil based lubricant for drilling fluids according to claim 1 characterised in that: The preparation method of the epoxy palm oil comprises the following steps: a. preparing an epoxidizing agent: 7 parts of acetic acid or formic acid, 18 parts of hydrogen peroxide and 0.1 part of concentrated H2SO4 are weighed, and then mixed uniformly at a temperature of 40°C to prepare the epoxidizing agent; the concentration of the hydrogen peroxide is 30%; b. epoxidation reaction: 35 parts of palm oil are weighed, heated and warmed to 40°C, and then the epoxidizing agent prepared in step a. is added dropwise at a constant speed, and the dropwise addition is completed within 1 h, and then the reaction is performed at a temperature of 65°C for 6 h; c. after the reaction is completed, the reaction system is allowed to stand and stratify, the lower layer of waste liquid is removed, and the upper layer of oil is washed with hot dilute alkali solution, and then washed with distilled water until neutral, and then dehydrated and dried.

3. A palm oil based lubricant for drilling fluids according to claim 1 characterized in that: The emulsifier is glycerol monooleate.

4. A palm oil based lubricant for drilling fluids according to claim 1 characterized in that: The pour point depressant is hydroxy hard fat.

5. A palm oil based lubricant for drilling fluids as claimed in claim 1 wherein: The anti-wear and friction-reducing agent is a metal salt of dialkyldithiophosphoric acid.

6. A palm oil based lubricant for drilling fluids according to claim 5, characterized in that: The anti-wear and friction-reducing agent is zinc dialkyldithiophosphate T203.

7. A palm oil based lubricant for drilling fluids according to claim 1 characterized in that: 65% of the epoxy palm oil, 10% of the emulsifier, 10% of the antioxidant, 5% of the pour point depressant and 10% of the anti-wear and friction-reducing agent.

8. A palm oil based lubricant for drilling fluids as claimed in claim 1 wherein: 90% of the epoxy palm oil, 0.1% of the emulsifier, 0.1% of the antioxidant, 0.1% of the pour point depressant and 9.7% of the anti-wear and friction-reducing agent.

9. A palm oil based lubricant for drilling fluids according to claim 1, characterized in that: 79.9% of the epoxy palm oil, 5% of the emulsifier, 5% of the antioxidant, 10% of the pour point depressant and 0.1% of the anti-wear and friction-reducing agent.

10. A method for preparing a palm oil-based lubricant for drilling fluid according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: Step S1. adding the epoxy palm oil into a closed reaction kettle, adding the emulsifier, heating and stirring until the temperature is 50°C, and then stirring until the emulsifier is completely dissolved; Step S2. adding the antioxidant and stirring until uniform; Step S3. adding the pour point depressant and stirring until uniform; Step S4. finally adding the anti-wear and friction-reducing agent and stirring until completely dissolved to obtain the palm oil-based lubricant.

Images